Automatic safety signal system for railways.



e. B. GRAY.

AUTOMATIC SAFETY SIGNAL SYSTEM FOR BAILWAYS.

AI'PLIOATIOH IILED IA! 11. 1907.

Patented Jan.5, 1909.

3 SKEETE-SHBET 1.

W1 nmssm A TTORNE ys G. B. GRAY. AUTOMATIC SAFETY SIGNAL SYSTEM FOR BAILWAYS.

APPLICATION FILED MAY 11. 1907. I

Patented Jan. 5, 1909.

A TTOR/VE Y5 SHEETS-SHEET 2.

ppy TNESSES APPLIOA'I'IOK FILED MAY 11. 1907.

- Patented Jan. 5, 1909.

3' SHEETS-SHEET 3.

W1 TNESSES A TTOR/VE Y5 GARDNER B. GRAY, .OF PITTSBURG, PENNSYLVANIA.

AUTOIA T IC SAFETY SIGNAL SYSTEM 1 03 RAIL-WAYS.

spoc ificatlon o t Letters Patent.

Patented Jan. 5, 1909'.

Application flied Icy 11, 1907. Serial No. 878,071 h Pittsbur in the county of Allegheny and State of ennsylvania, have invented a new and useful Automatic Safety Si a1 System for Railways, of which the to owing is a specification.

This invention has reference to improvements in automatic safety signal systems for railways, and its object is to provide a block system which will give both visual and audible signals to the engineman on a proaching a danger zone, and will revent tlie possibility of accident from co ision because of the presence of such danger zone.

The improved system is entirely auto matic so ar as the display or sounding of signals is concerned, and the making of a permanent record of such signals, and also as to the application of the brakes should the engineman from carelessness or design or from any other cause pass into a danger zone after having been warned that the train was approaching such zone.

this invention provision is made whereby the engineman may set the various signals to the position indicating safety after they have been moved automatically to the caution or danger osition, but thearrange- 'mentis such that t e restoration of the signal devices to the safety position can only be made after the signals have been moved to the caution or danger position, 'as the case may be, and any manipulation of the restoring means by the engineman prior to or during the setting of the signals at caution or danger will be futile, whether such manipplatiion be performed maliciously or thoughtess y.

By the present system the railway line is divided u into blocks of a propriate length, and suita le indications 0 the presence of a danger zone, which may be represented by a moving train in the ordlnary course of traffic, or a stalled train, or a wreck, or any other condition which would present an element of danger to another train, will be transmitted to the next block in advance in such manner as to indicate to the engineman of an oncoming train that a danger zone is imminent and to transmit to the second block in advance a cautionary signal to the en ine whereby cautionary s als only are given to the engineman two b ocks away from'the danger zone, while at the block immediately receding ,the danger zone not only are anger signals transmitted to the engineman but the train is automatically sto ped by a suitable a plication of the air-bra es.

Now, t ese various operations are performed by means of but two main conductors along the track between the various block stations, and the system is arranged to work on a normally closed circuit. 'Also, provision is made whereby should the normal condition of the installation become changed,

as by the breaking down of the insulation used at various points, or should other breaks occur, suitable cautionary signals will be dis played and'thus give notice of the inoperative or defective condition of the system.

Again, the system is so arranged that should.

an engineman ignore the signals given and enter upon a danger zone and so have his train stopped by the automatic ap lication of the brakes, the latter cannot be re eased so that the trainmay proceed until the train has come to a full stop since the releasing mechanism for the brakes, when automatically set by the o ration of the block system guardin the anger zone, is so timed that it can ony be mani ulated after an appreciable time during w ich the train has come to a full stop.

The construction of the system and the objects and purposes thereof willbe best understood b a consideration of the manner in which the system is installed, and such installation is shown in the aocom anying drawingls forming part of this spec cation, in whic Figure 1 is a diagrammatic re resentation of .the installation at one of the'b ock stations and the installation on the cab of an engine, which, in this figure, is shown in conjunction with a particular block station; Fig. 2 is a diagram illustrating two other bloc-k stations, which may be taken as joining the left-hand end of the system shown in Fig. 1 Fig. 3 is a stations, showing in greater detail a portion of the installation at the block stations.

In thefollowing description the block stations will be referred to as A, B, C, D and E,

the stations A and B being shown in Fig. 2, the station C being shown in Fig. 1, and the stations D and E being shown in Fig. 3. For convenience, these five stations shown in the three figures will be considered together, as though the diagram occu ied but one sheet of drawings and was em raced under one figure designation. It will be understood, of course, that there will. be as many block stations as may be desired. I

At each station the rails 1 and 2 are insulated from each other at points 34, one directly opposite the other, and at other points 56, which are diagonally disposed. The insulation sections 34 and the other insulation sections 56 rovide short track sections 7 and 8 at eac block, the section 8 being considerably shorter than the section 7. Bridged across between the sections 7 and 8 is a battery 9, and another battery 10 is bridged across the rails 1 and 2 at or between each block station. These batteries will be hereinafter referred to. In the drawings the running gear of a locomotive is represented simply by contiguous Wheels and axles, and as but two trains will be particularly considered in the following description, these pairs of wheels and axles will represent two .1000- motives X and Y.

Considering, first, the block stations, the circuits and apparatus located at each, as shown in the drawings, will appear from the following description. Extending from the rail section 7 there is a conductor 11 leading to an electro-magnet 12, and this magnet is connected by a conductor 13 to the other rail section 8. This places the magnet 12 normally in a closed circuit charged by the battery 9 and the magnet is therefore normally excited. This magnet 12 controls two armatures or contact levers 14 and 15. In the path of the armature 15 there is a contact point forming the terminal of a branch conductor 16 coming from the conductor 1 1, and the armature 15 is normally out of contact with this branch conductor 16, that is, so long as the magnet 12 is energized. The armature 14 is connected by a conductor 17 to the rail 1 to the left of the station around the insulated rail 7, and the other rail 2 to the left of the station beyondthe rail 8 is connected by a conductor 18 to a magnet 19, the othe1 terminal of which latter is connected by a conductor 20 to an armature 21 in the path of which is the termimal of a bridging conductor 22 having its other terminal in the path of the armature 14, which latter is maintained in normal contact with the adjacent terminal of the conductor 22 when the magnet 12 is energized. A branch conductor 23 connects the armature 15 with the conductor 18.

The armature 21 is controlled by a magnet 24, one terminal of which is connected to the rail 2 to the right of the station beyond the insulation 4 by a. conductor 25, while the other terminal of this magnet is connected by a conductor 26 to an armature or switch lever 27, in the path of which is one terminal of a bridging conductor 28, the other terminal of which is in the path of an armature lever 29 connected by a conductor 30 to the rail section 8. Adjacent to the connection of the conductor 25 with the rail section 2 another conductor 31 is connected to said rail section 2 and leads through a battery 32 to terminals 33, one of which is in the path of-a switch lever 34 connected to another terminal 35 in the path of an armature lever 36, which latter is connected by a conductor 37 to the rail section 8 adjacent to the connection therewith of the conductor 30. Branched off from the conductor 31 is another conductor 38, including a battery'39, and this conductor 38 leads to a terminal 40 in the path of the armature lever 34 on the side opposite one of the terminals 33,.the other terminal 33 being in the path of the armature lever 27.

Controlled by the magnet 19 is an armature lever 41 connected by a conductor 42 to two terminals 4344, and between these terminals 43-44 are other terminals 4546 connected by a conductor 47 to a branch conductor 48 leading to another conductor 49, which latter includes a battery 50 and an electro-magnet 51 and leads at one end to a terminal 52 and at the other end to an arma ture lever 53 in the path of which is the terminal 52. The conductor 48 also leads to a terminal 54 in the path of an armature lever 55, from which latter leads a branch conductor 56 to a terminal 57 in the path of the armature lever 53, and the armature lever is also connected to one of the line conductors 58, while the other line conductor 59 terminates at the station under consideration in a contact point 60 in the path of the armature lever 41.

The magnet 51 controls two armature levers 61 and 62 forming the terminals of a circuit including a battery 63 which charges the main line clrcuit conductors 58 and 59. The armature levers 61 and 62 have in their paths the contact terminals 43-and 45, and 44 and 46, respectively, and constitute a polechanger for the battery 63 for a purpose which will hereinafter appear. The main line conductors 5859 terminate at the next succeeding station in a magnet 64, shown more in detail in Fig. 4. This magnet controls the armature levers 29, 36 and 53, while one pole 65 is extended and carries a polarized armature 66 between the poles 67 and 68 of the magnet 51, which latter controls the armatures 61, 62 and 55. The armature 66 car ries or controls the switch levers 27 and 34.

The circuits just described are common to all the stations along the line of the railroad, but before entering into an explanation of g the of the system it will be necessary to trace out the cab circuitsand the mechanism controlled thereby. Thecab system is shown in Fig. l'as carried by engine but is the same as that carried by all the ether ,en ines. The two axles 69-70 of the engine are insulated one from the other {but each axle and its wheels are electrically connected. The axle 69 is connected by a conductor 71 and the axle is connected by a conductor 72 to the two arms of a doublearm switch 73, in the path. .of which arms are two contact terminals 7 475 and a double, common terminal 76, so that this switch 73 may be operated as a ole-changing switch for a ose which will hereinafter a pear. Th terminal 74 is connected to a con uctor 77 and the terminal 7 5 is also connected to the sameccnductor77 through a branch conductor 78, while the two common terminals 76 are connected to a conductor 79. The conductor 77 leads to an armature lever 80 and in the path of this lever there is a terminal 81 .of- ,a conductor 82, which latter leads to a magnet 83 and from thence to a battery 84, the ether side of which latter is connected to the conductor 79. The conductor 77 is also connected by a branch conductor 85 to a terminal 86 in the path of an armature lever 87 which, in turn, is connected by a conductor 88 to the conductor 82 before mentioned. Again, theconductor. 77 is 0on nected by a branch conductor 89 to a contact terminal 90 in the path of an armature lever 91, the other end of which is connected by a conductor 92 to an electro-magnet 93 and leaving the latter is connected tothe battery 84 on the same side to which the conductor -82is connected. The conductor 92, after leaving the armature lever 91 but before reaching the magnet 93, is connected to another conductor 94 leading to a contact or terminal 94 to be hereinafter referred to. There is another terminal 95, also to, be hereina fter referred to, connected by a conductor 96 to the conductor 82 before referred to, and the conductor 96 is connected by a branch conductor 97 to a terminal 98, to be hereinafter referred to.

Under the influence of the magnet 83 there is another armature lever 99 connected by a conductor 100 to an electro-magnet 101 which, in turnyis connectediby a continuation of the conductor 100 to a conductor 102, including a battery 103. In the path of the armature lever 99 is a contact terminal 104 connected by a conductor 105 to another conductor 106 having one terminal connect- .ed to an armature lever 107, under the infiuence of the magnet 93, and the other terconnected to the battery 103. The conductor 1%, at a point between its junc tion with the conductor 105 and the battery 103, is connected to a branch conductor 108 in which is included a signal recorder 1 09,

the other side of which is connected by a conductor 110 to a contact terminal 111 in the path of the armature lever 107 On the other side of the armature lever 107 is a contact terminal 112 from which leads a conductor 113 to a solenoid coil 114, to be hereinafter. referred to, and from this. coil 114 there leads a conductor 115 .connectedto the conductor 100 and thence to the battery 103.. Branched off from the conductor 113 is an- .other conductor 116 leading to a signal-indicating device 117 which, in turn, is connected by a conductor 118 to the conductor 1500 and thence to the battery 1-03.

The signal device 117 is arranged to give visual signals both for caution and The conductor 118 is connected to the ot r side of this signal device 117 by a branch conductor 119 and the other terminal of this other side of the signal-indicator 117 is con nected by a conductor 120 to a solenoid 121, the other side of which is connected by a conductor 122 to the conductor 115 before referred to. The conductor 118 is also connected by a branch conductor 123 to the recording device 109, from which leads anreferred to.

Branched off from the condnctor 79 before the latter reaches the battery 84 is another conductor terminating in a contact 131 in the path of a manually o. e-rated key 132, and also in the ath of this ey, the contact 94 is located. The key 132 is connected by a branch conductor 133 to a conductor 134 between its terminals, thisv conductor 134' having at one end a contact terminal 135 and at the other end a contact terminal 136, the latter being opposite the contact 125 before referred to, and between which, that is, between the contact terminals 125- and 136, there is introduced a bridging arm 137. On the same side of the arm 137 as is the contact 125 and contiguous thereto is -an-' other contact 138 connected by a conductor 139 to the conductor 115 between the battery 103 and the connection with the con ductor 122. On the same side of the bridging arm 137 as is located the terminal 136 there is another terminal 140 connected by a conductor 141 to another te minal 142 contiguous to the terminal 95, and these terminals 95 and 142 are in the path of a bridging conducting arm 143.

The bridging arm 137 is carried at the end of a curved or Bourdon tube 144 connected by a branch pipe 145 to an air pipe 146 lead ing at one end into a cylinder 147 and at the a valve 165 in the pipe 155.

other end connected to a valve 148 controlled by the solenoid 121. The valve 148 is connected by a pipe 149 to another pipe 150 comin from an air-supply tank 151, and from t is pipe 150-extends another pipe 152 to a cylinder 153, to be controlled in a manner to be described. The cylinder 147 is connected to the cylinder 153 by a pipe 154 and from this pipe 154 there branches another pipe 155 connecting to a cylinder 156 in which is located a piston 157 on one end of a piston-rod 158, the other end-of which enters a dash-pot 159, and between the cylinder 156 and the dash-pot 159 the piston-rod 158 carries a contact arm 160 to which is connected one end of a conductor 161, the other end of which is connected to a contact terminal 162 alongside the contact terminal 135 and arranged to be bridged by a conducting plate 163 on one end of a lever 164 carried by This lever 164 terminates at the outer end in a fork 166 in the path of a finger 167 on the end of a pistonrod- 168 controlled by a piston (not shown) in the cylinder 153. The cylinder 147 be fore referred to is also provided with a piston (not shown) terminating in a piston-rod 169 arranged to control the throttle lever 170.

The air tank 151 is connected by another pipe 171.to a valve 172 under the control of the solenoid 114. From this valve 172 there leads a pipe 173 from which rises another pipe 174 terminating in a whistle 175. Air coming through the pipe 173 also enters a small tank 176 through an orifice of a size to revent rapid flow, so that there is a time imit before the air in the tank 176 equals the supply pressure. This tank 176 is connected by a conductor 177 to a curved or Bourdon tube 178 carrying at its end the contact arm 143 before referred to.

The tank 151 is also connected by another pipe 179 through a manually operated valve 180 to a curved or Bourdon tube 181, and this pipe 179, through a branch pipe 182, feeds air to a cylinder 183 containing a piston 184, to the piston-rod 1 85 of which'is connected a contact plate 186 movable into contact with the end of the Bourdon tube 181. The contact plate 186 is connected by a conductor 187 to the conductor 71, and the Bourdon tube 181 is connected by a conductor 188 to the conductor 72.

Having set forth the various circuits and instrumentalities comprised within the system, I will now proceed to describe the operation. Now, let it lee-supposed that there is a train drawn by the locomotive X upon a block approaching station A and which, for convenience, may be called block A. The truck of the engine short circuits the battery 10, and, therefore, shunts the current from the circuit through the conductor 18, magnet 19, conductor 20, armature lever 21, branch conductor 22, armature lever 14 and conductor 17. This so weakens the magnet 19 that its armature 41 drops and breaks the mainbattery circuit at the contact point 60. This denergizes the magnet 64 at station B and the armatures 29, 36 and 53 move away from the respective contacts, which 0 ens the circuitsfed by the batteries 32 an '50. Meanwhile, the armature 53 makes contact with the terminal 57. .Now, the armature 66, shown in Fig. 4, is normally polarized by the main circuit magnet 64 and the freeend of this armature is normally within the influence of the strong magnetic field of the polar extensions 67 and 68 of the magnet 51 by which this armature 66 is actuated when in operation. When the magnet 64 was deenergized, the armature 66 was magnetically neutralized and meanwhile, because of the break in the circuit of the magnet 51 caused armature 66 therefore dropped by gravity or spring at the. same time the armature levers 29, 36 and 53 dropped. Under normal conditions the armature levers 29 and 36 are in connection with the insulated-rail sections 7 and 8 through the conductors 30 and 37, although a bridge formed by these last-named conductors and the conductors 25 and 31 normally connects these insulated rails with the main track leading to station B. Now, when the lever 53 broke the circuit of the magnet 51, the latter released its armatures 61 and 62 which have therefore moved away from the contacts 43 and 46 and made contact with 45 and 44, thus reversing the current from the main battery 63 through the main circuit conductors 58 and 59 and the magnet 64 at station 0, thereby reversing the polarity of the armature 66 of this station and causing the armature levers 27 and 34 to leave the contacts with which they were in engagement and engage the contacts 33 and 40, respectively. When the switch levers 27 and 34 moved away from the terminals of the conductors 28 and 31 they broke the normal bridge between the rails 7 8 and the main track rails 1-2 beyond the station C, but another bridge was immediately formed between the conductor 31, the conductor 38, the contact point 40, the switch arm 34, the contact point 35, the armature lever 36 and conductor 37, thus including the master battery 39. Under these conditions, there is on the track at station C between the track section 8 and the succeeding track section 2 toward station D a difference of potential equal to that of the master battery 39.

The conditions are how such that an engine Y approaching station C in a direction to move toward station B will receive a caution signal. Let it be assumed that the forward trucks of the engine Y have passed the insuscenes la ion 4 and moved on to the trac se tion 7.-8. Now, current from the master bat tori 39 will flow to the contact lever 34, to on through the armature 35, thenceby eonductor 37 to the track section 8, and by way of the Wheels and H16 69 to the conductor 71, thence by the corresponding arm of the switch 73 to conductor 79 and throu h the battery 84 in opposition thereto, an from thence to the magnets 83 and 93, returning by wa T of conductor 77, switch 73, conductor 72, a e and wheels 70, conductor 31, back to the battery 39. This Ipass e of the current from the batter 3,9 t roug the battery 84 will neutralize t e latter and cause a flow of current in the reverse direction through the magnets 83 and 93, thus instantly reversing their clarity. This will tend to repel or kick t e armatures of both magnets away from their respective contact points, but the armature 91 will break the contact at the point 90, and since this armature and contact point are in series with the master battery 39 and cab battery 84 and the magnet 93, that particular circuit is broken and the magnet 93 becomes deenergized and so remains while the caution signal is being exhibited and until it is again energized in a manner which will presently appear. While the action just described has been taking place the armature lever 107, which is under the control of the magnet 93, has also dropped from contact 112 and thus broken the circuit from the contact 112 through the conductor 113, branch conductor 116, the caution end of semaphore signal 117, throu h conductor 118 and conductor 100 to the attery 103, thence returndisplayed on the break of this circuit, and,

ing by conductor 106 and armature 107 to the contact point 112. The semaphore caution or green signal is soarranged as to be consequently, is now visible to the engineman. The armature lever 107, however, has

dropped into contact with the point 111,thus

closing the circuit through conductor 110, register 109 on the caution or green side, branch conductor 123, conductor 118, conductor 100, battery'103, conductor 106 back to lever 107, this register being arranged to operate on the closing of the circuit. Moreover, when the lever 107 broke contact at 112 it also opened another circuit which may be traced as follows -from point 112 through conductor 113 to solenoid 114, thence by con- I ductor 115 back to the battery 103 and by conductor 106 to the lever 107. This releases the solenoid 114 and causes the opening of the valve 172 which admits air through pipes 173 and 174 to the whistle 175. This also-admits air to the Bourdon tube 178, causing the latter to straighten sufliciently to move the contact arm 143 into position to bridge the contacts 95 and 142 and thereby close the gap normally 0 en at the contact points 95 and 142 in the ridge circuit from through the magnet 93 and back to the battery 84. Now, the engineman by depressing the key lever 132 may close the circuit between the lever 132 and the terminals 94 and 131, thus exciting the magnet 93 and restoring the armature levers 91 and 107 to their normal positions, thereby closing the air valve 172 and moving the arm 143 away from the contacts 95 and 142, thus openin the gap between them as before. During a this time the magnet 83 has not been affected by the opposition of the battery 39 since there is a by-path around its armature 80 through the conductor 88, armature'87 and conductor 85 back to the conductor 77.

The engineman now runs with caution until he reaches station B, where the appliances are assumed to be set for danger. At this station, however, the bridging circuit around the insulated joints 3 and 4 is broken because the magnet 64 is de'e'nergized and the levers 29'and 36 have fallen away from the respective contact points. Therefore, the circuits fed by the battery 84 and including the magnets 83 and 93 are broken and the armatures 80 and 91 instantly drop, breaking the circuits at the points 81 and 90. The

armature lever 107 also breaks the circuit at point 112, thus releasing the solenoid 114 and sounding the Whistle, and bridging the contacts 95 and 142 as before. Now, however, the armaturelever 80 breaks contact with the point 81,. which opens the gap at this point in the circuit between the conductors 72 This ap, however, is bridged for an instant by the y-path 79, 82, 88, 87 and 85, but such by-path is quickly broken since the. lever 99., dropping at the same time as the lever 80, opens the circuit at point 104, thus breaking the circuit by way of conductor 100 and magnet 101 through the battery 103, thence-by conductors 106 and back to the contact point 104. The magnet 101, thus becoming denergized, breaks the bridge at the point 86, and thus gaps are opened in a circuit between the conductors 71 and 72 at the point 90 and point 111, thereby leaving the magnets 83 and 93 deenergized until again excited by the lever 132. Meanwhile, the contact lever 128 has dropped in unison with the lever 87, opening thecircuit at point 127. This circuit may be traced through conductor 126, battery 103, conductor 118, branch conductor 119, dan er side of the signal apparatus 117, thence y conductor 120 and conductor 129'back to the lever 128. The danger indicator operates on the break of the circuit, causing the semacontact arm 137 from the contacts 136 and 140 into bridging relation with the contacts 125 and 138. This destroys the bridge that could be established through the conductors 96 and 134 to the key 132. Now, when the arm 137 is lifted into contact with the points 125 and 138 there is established a circuit which may be traced as follows: from the point 138 by branch conductor 139 to conduc tor 102 thence through the battery 103, conductor 106, conductor 108 to the danger side of the register 109, thence by conductor 124 to the terminal 125. This causes registration of the danger signal.

While the operations just described have been taking place the air valve 148 has admitted air into the cylinder 147, causing the piston-rod 169 to engage the throttle ever 170 and move it to shut ofi steam from the engine. This action causes the uncovering of a port leading from the cylinder 147 into the pipe 154 and through this pipe air is admitted to the cylinder 153, moving the piston controlling the piston-rod 168 and uncovering a port which admits air to the brake mechanism of the train through a main air pipe 189 receiving air from the reservoir 151 through the pipes 150 and 152. Air also passes by ipe 155 through the valve 165 into the cylin' er 156 beneath the piston 157, thus lifting the arm 160 upward out of contact with the terminal 98. The arm 160 is so held until the movement of the pistonrod 168 out from the cylinder 153 brings the finger 167 into engagement with the fork 166 and causes the air valve 165 to be closed, meanwhile bringing the bridging piece 163 across the terminals 135 and 162. Since the air has been cut off from'the cylinder 156 by the closure of the valve 165 the plunger in the dash-pot 159 slowly sinks and at the termination of a predetermined time period it carries the arm 160 into contact with the terminal 98. The operation just described causes the bridge from the key lever 132 through the branch conductor 133, conductor 134, terminals 135 and 162, conductor 161, arm 160, terminal 98, branch conductor 97, conductor 96, magnets 83 and 93, battery84, conductors 94 and 130 and terminals 94 and 131, to be completed except at the said terminals 94 and 131 where the circuits may be completediby the depressing of the lever 132.

During the operation just described the brakes have been set and the train is brought to rest while the dash-pot plunger is traveling in a direction to bring the arm 160 into comcidence with the terminal 98. Now, when the gaps between the terminals 135 and 162 and between the arm, 160 and terminal 98 have been closed, the e eman can depressthe key lever 132 to c ose the circuits y the terminal94 and terminal 131. The magnets 83 and 93 are at once energized and their armatures are lifted to their normal position. At the same time the contact at point 104 is closed and the magnet 101 is en-, ergized and lifts its armatures 87 and 128 to closethe contacts at 86 and 127, respectively. This causes the ener 'zation of the solenoid 121, thus releasing t e throttle and brakes and permitting the engineman to start the train.

In the foregoing description reference has also be understood that the magnets are .wound with due re ard to the oflice they are to perform. It wil likewise be evident that the register 109 and the sema hore signal device 117 may be of an suitable structure, which need not be consi ered in detail in the description of the present system. Also, the severa mechanical structures referred. to may all be of known construction, and, therefore, will be sufficiently understood from the diagrammatic representations found in the drawings, without any further detailed description. Furthermore, the batteries will.

be of suitable size and construction to furnish such current as may be necessary for the operation of the system, and, if desirable, the key lever 132 maybe replaced by a simple push-button.

1 In the foregoing description no account has been taken of the features ofthe system whereby careless or malicious interference with the operation of the system, on the art of the engineman, is prevented, and these features of the system will now be considered.

It will be understood, of course, that the several mechanisms and circuit connections are all securely sealed against tampering by the engineman, and the only point in the whole system which the engineman can control while the train is in motion is the key lever or push-button 132.

moms

while a ain there is another bridge circuit.

under t 0 control of this key lever normally closed at the contact 98 through the arm 160, it is normally open at the contact points 135 and 162. 1 Therefore, under normal conditions, no results can possibly beobtained by the closing of these circuits at the key lever or push-button 132. 'Now, when the magnet 93 causes the break of the circuit at the point 90 due to the denergization of the said magnet 93 by the position of the instrumentalities when set to give a caution signal, the caution semaphore is displayed and the cantion register is operated, while air is admitted to the whistle and is simultaneously admitted to the tank 176. But since the passage to the tank 176 is more or less throttled, a predetermined time period elapses before the Bourdon tube 178 operates to close the contact between the terminals 95 and 142. Thus, before the restoring bridge circuit can be made active by the manipulation of the key lever 132 the various operations incident to the conditions present when a train has reached the cantion zone, have all been performed, and it is only after the completion of these various operations that the engineman can by any possibility affect the circuit conditions, and then the only result of the closing of the circuit by the key lever 132 is to restore the normal running conditions and at the same time renew the non-interference features.

When the danger zone is reached both magnets 83 and 93 are dcenergized and their armatures are dropped. As before explained, this causes the solenoid'114 to open the air valve 172 and sound the whistle, and then, after a short time interval, to cause the closurev of the circuit across the contacts 95' and 142. Now, the closing of these contacts would so complete the bridging circuit c011- trolled by the key lever 132 that the engineman might interfere with the further operation of the system were it not for the fact' that the denergization of the magnet 83 had caused the magnet 101 to become deener 'gized and thus released the solenoid 121 and o ened the air valve 148. Because of the s uggish action of the air upon the Bourdon tube 178 the Bourdon tube 144, which, be-

"cause the air has free access thereto, acts quickly, has caused the rupture of the circuit at the points. 136 and 140 in advance of the closure of the circuit at thepoints 95 and 142. The bridge circuit from the key throughthe conductors 9.4 and 134 thus remains broken. At the same time the air entering the cylinder 153 has closed the other bridge circuit through the key 132 at the points 135 and 162, but it has also broken this circuit at the point 98 by moving the arm 160 away therefrom, and it is only after a predetermined time interval that the arm 160 is again brought into contact with the terminal 98. Thus, in each case, there is an l appreciable time interval before an active circuit can be closed by the manipulation of the key 132, and during this time the several operations described and due to the conditrons present in the dan er zone, have taken place. Now, when the key 132 is depressed and completes the bridge circuit the parts are all returned to thei'r'norrnal condition, when interference on the part of the engineman is out of the question.

- It will be seen from the foregoing that unning or standing still, can the engineman by depressing the key or push-button 132, or in any other manner, either prevent, falsify or otherwise interfere with the automatic operation of the cab appliances. There is one specific condition, however, which might arise under which the engineman should possess means under his control for evading the rigid restrictions of the system.

Suppose that by some chance an engine should stop at station B with the trucks directly upon the insulatin sections 34 and with the bridge between tlie section 8 and the track 2 broken, which is the condition when station .13 is in the danger zone. Under and all the operations attendant to the same will be performed, but since the circuit through the conductors 71 and 72 is broken at the insulating sections 34, the closin of the circuit by the key 132 will have no e ect and the train will be stalled since the brakes will continue in their" applied condition and the engine'manwill be unable to either rc- Provision, however, has been made to meet such an emergency. Beneath the engine, out of reach of the enginemanwhen the engine is moving, there 1s located the manual valve 180 in the pipe 179 leading to the Bourdon tube 181 and, by the branch pipe 182, to the air cylinder 183.. Under the conditions just described the engine is, of course at a standstill, and the engineman may then step off the engine and reach beneath the same and move the valve 180 to admit air from the reservoir 151 to the pipe 179. This air enters the tube 181 and tends to straighten the same and simultaneously enters the cylinder 1'83 and, acting on the piston 184, causesthe piston-rod 185 and contact plate 186 to move toward the contact end of the tube 181. In the meantime, however, the r straightening of the tube 181 has moved the l contact end thereof out of the path of the der no conditions, whether the tram be run-] these conditions, the danger signal will be set lease the brakes or to again open the throttle.

I be of the self-closing type, and thus shuts off referre air from the tube 181 and the latter returns to its normal bent condition, bringing its end into contact with the plate 186. Since the air is alsoshut off from the cylinder 183 the piston 184, which, inconjunction with the c linder 183 may be made to operate after t e manner of a dash-pot, moves slowly toward its initialposition, thus carrying the contact plate 186 by the contact end of the tube 181. Now, b way of the conductors 187 and 188 and t e tube 181 and contact plate 186 there is established a shunt across the conductors 71 and 72. The time element enterin into the operation of the devices just 5 to is sufiieient to enable the engineman to again mount into the cab and press the key or button 132 and thereby reestablish .the normal running conditions, and the time consumed in the return of the iston 184 to its initial position is such that t e engineman may start the engine and carry the wheels from off the insulating sections 3-4.

Now, the emergency mechanism just described cannot be tampered with because so long as the valve is open the tube 181 is straightened and the circuit is broken. Hence, it is only after the valve 180 has been closed to allow the escape of the air subsequent to the introduction thereof into the tube and cylinder, that the device becomes" operative. c

It will be understood, of course, in relation to this emergency device, that all the structure except the valve 180 is inclosed and sealed against tampering by the engineman. Therefore, in view of the mode of o eration, it will be seen that it is not within t 1e power of the engineman to cause the closure of the shunt circuit across the conductors 71 and 72 except in the manner described, and then only after a limited period of time. Also, this can only be done when the engine is at a standstill, and need only be done under the rarely occurring conditions of an engine stoppingwith its truck upon the insulating sections 3 and 4. r

The switch 73 is a simple pole-changing switch by means of which the cab circuit to the safety of the system, and, therefore,

due warning must be signaled to' a proaching trains, while the record of suc signals will also give notice that an inspectors attention is required. Let it be supposed that to track section 2, is thus diverted to a circuit which may be traced from track section 2 through conductor 31, battery 32, armatures 34 and 36, conductor 37, track section 8 and across the bridge around the broken down insulation 4 to the track 2. The magnet 24 is thus shunted, causing the armature 21 to be dropped and break the circuit with the conductor 22, "thus breaking the circuit from the magnet 19 through the conductor 20, armatures 21 and 14, conductor 17, track section 1, thence by battery 10, bridging the track sections 1 and 2, back through the conductor 18 to the magnet 19. The result of this is that the magnet 19 is denergized and its armature 47 is dropped away from the contact 60, thus breaking the main line circuit 58-59 between the stations and setting the devices at station C for danger and at station D for caution, the same as though.

engine X had entered upon the track section controlling station B. This, of course, gives warning to any approaching'train that there is trouble ahead. Again, suppose that the insulating section 3 breaks down. There is then established a circuit from battery 32, through conductor 37 to the rail section 8, thence throughbattery 9 to the rail section 7, around the bridge across the broken down insulation 3 to the track section 1, then across by the battery 10 to the rail 2 and by conductor 31 back to the battery or, the return circuit from the track 1 to the track 2 may be through conductors 17 and 20 of the next station and by magnet 19 and conductor 18 back to the track 2. In either case, the battery current is diverted from the magnet 24 and the latter is so weakened as to drop its armature 21 and establish the danger conditions at station C and caution conditions at station D.

Now, let is be assumed that the insulating joint'5 breaks down. Then the first arriving engine which passes upon and spans the inlishment of the usual conditions for danger and caution to the stations ahead, as before.

Likewise, should the insulating section 6 break down, an arriving train shunts the magnet 12-and the magnet 19 1s again weakened and drops its armature and the danger and caution conditions again prevail.

The entire electrical system is on normal closed circuit andit will be seen that should there be a break in any of the circuit connections upon the track, or shouldthere be a broken rail, or should a switch be misplaced,

the danger and warning signals would be transmitted in the manner already descri bod. Or should a detached truck or a pair of wheels, by any chance, lodge directly upon the insulated rail sections 7 and 8 and so become amenace to traffic, these rails being shunted the magnet 12 will be weakened and the signals will be transmitted as before. Again, should the main conductors 58 and 59, or either of them, be ruptured, the deenergization of the magnet 64 will cause the establishment of the danger and cautionary conditions in the succeeding stations. 01 should a circuit in the cab break down, thr' danger conditions are immediately established and the train is automatically stopped. The system requires but one complete main circuit, that is, there are but two main circuit conductors extending from station to 7 station instead of four or more, as heretofore,

while at each station the combination relay, illustrated separately in Fig. 4, acts as the intermediary which virtually links adjacent mains and forms of them a completeinterchain through which the varied signals find their pro er destinations. It is by reason of this p0 arized pole-changer, shown in Fig. 4, that when caused to operate through the break of a main circuit connecting the station to the preceding station and so setting the devices at the station under consideration that danger signals will be transmitted to the cab of an oncoming train, that the circuit connections to the succeeding station are not broken but the current simply diverted througha path which will maintain the circuit connections intact, but by reversing the direction of current will cause the polarized relay at the said succeeding station to establish conditions which will cause cautionary signals to be dis layed and sounded on an engine entering t e caution zone.

I claim 1. In an electric safety signal system for railways, normally closed, charged electric circuits on moving trains, signaldevices on.

the trains held inactive by said closed circuits, other electric circuits disposed along the line of way and each ada ted to be coupled into the normally closer charged train circuits, a normally inactive source of current for each of said circuits along the line of way sufiicient to overpower the charging source of the .closed, charged train circuits, and means for including said normally inactive current source in the respective circuits along the line of way.

2. In an electric safety signal system for railways, normally closed, charged circuits on the train, signal devices on the trains held inactive by the said train circuits, norsource of current sufiicient to overpower the controlled by the switch mechanism at the mally closed electric circuits along the line of way coacting' with the train circuits, and means for includingin any one of the circuits along the line of way a normally inactive 70 charging source of the train circuit one. change in the normal condition of the closed circuit along the line of way to cause the op cration of an appropriate signal.

3. in an electric safety signal system for railways, block stations along the line of way; continuous rail sections between the blocks; insulated rail sections interposed between the continuous rail sections at the block stations; charged electric circuits at each station including the rails approaching the station; an electrically operated switch mechanism controlled by said circuit; another charged circuit leading to the next station and including the aforesaid switch and controlling a polarized, switch-operating mechanism, and normally closed, charged electric circuits at each stationcontrolled by the polarized mechanism which, in turn, is

preceding station. i

4. In an electric safety signal system for railways, block stations disposed along the line of way; a normally closed, charged electric circuit at each station including the traflic rails approaching said station; a magnet in said charged circuit; a switch under the control of said magnet; anothernormally closed, charged electric circuit including said switch and extending from one station to the next station; a polarized circuit-controlling and pole-changing mechanism at each station controlled by the charged circuit coming from the preceding station; insulated traffic rail sections at each station, and charged electric circuits including said insulated sections of the trafii'c rails and also controlled by the polarized switch and pole changer.

5. In an electric safety signal system for railways, block stations disposed along the line of way; traffic rails having. insulated sections at each station; a normally closed, charged electric circuit including the traffic rails approaching the station and an electromagnetic switch-operating means; another normally closed, charged circuit including one of the insulated sections of the traiiic rails; switches included in said last-named circuit; another normally closed, charged electric circuit including a switch controlled by the first-named circuit and extending to the next succeeding station andther'e controlling the switches in the second-named circuit; and means whereby a break of circuit between two stations will cause a reversal of current through the circuit coupling the second station to the third station in order. a y r I a 6. In an electric safetysignal system for I 'cuits at said block stations; means for open-- railways, block stations arranged along the line of way; insulated rail sections included in the traffic rails at the stations; a normally closed, charged electric circuit at each station; a normally inactive-source of current; means at each station under'the control of the electric circuits coming from another station for including the normally inactive source of current; an open circuit including the trafiic rails on each side of the insulating points, andnormally closed, charged electric circuits on each train, arranged to close the normally open, charged, block-station circuit and responsive to the current from the normally inactive source at the'block station.

7 In an electric safety signal system for railways, block stations along the line of way; a charged electric circuit at each block station; another charged electric circuit upon atrain and arranged to be coupled with and overpowered by the source of current in the block-station circuit; other electric circuits upon the train, and electro-responsive means in the first-named train circuit arranged to control the other train circuits when coupled to and controlled by the source of current at the block stations.

8. In an electric safety signal system'for railways; block stations along the line of way; normally closed,.charge electric ciring the charged circuit at one block'station and reversing the direction of current flowing in the corres onding circuit in the next suc ceeding blocE station, and normally closed, train carried circuits arranged to be coupled to and operatively controlled by the reversed circuit at a block station to cause the actuation of a redetermined signal or set of signals, and to be placed on 0 en circuit by the open circuit at the other b ock station to cause the operation'of other predetermined signals. 7

9. In an electric safety signal system for railways, block stations alon the line of way; normall closed, charge electric circuits at said b ock stations; means for opening the charged circuit at one block station and reversing the direction of current flowing in the corresponding circuit in the next succeeding block station; normally closed, train carried circuits arranged to be coupled to and operativelycontrolled by the reversed circuit at a block station to cause the actuation of a predetermined signal or set of signals, and to be placed on open circuit by the open circuit at the other block station to causethe operation of other predetermined signals, and manually operative means on the train for restoring the normal conditions of the several circuits.

10; In an electric safety signal system for railways, a cab or train system comprising a normally closed charged circuit, another cirelectrical conditions causing rupture of the caution circuit. and consequent actuation of said signal under predeterminedtraflic conditions, and of the danger circuits, and the consequent actuation of the said danger signal under other predetermined traffic conditions.

11. In an electric safety signal system for railways, a cab or train system comprising a normally closed, char ed electric circuit; another normally close charged electric circuit under the control of the first-named circuit; air-brake and throttle-operating means under the control of the second circuit and rendered inactive so lon as this circuit is maintained intact, and b ock stations along the line of way with normally closed electric circuits and inactive to the cab circuits under normal conditions but rendered active thereto by a change'from the normal conditions.

12. In an electric safety signalfsys'temifor railways, normally charged electric circuits along the line of way, closed electric circuits on the trains controlling cautionary and danger devices, and means for establishing circuits along the line of way and within a predetermined distance of a point of danger, electrical conditions causing rupture of the 'train circuits controlling1 the danger .devices upon a train entering t e dan er zone, and thus effecting the actuation 0 said danger devices, said means also establishing in the circuits alon the line of way and within a greater (pre etermined distance from the point of anger, electrical conditions causing the rupture of the train circuits controlling the caution devices upon a train entering themore distant or cautionary zone.

13. In an electric safety signal system for railways, mechanically operated means upon a train for the actuation of cautionary and safety devices upon a train; normally closed electric circuits for holdin said devices in inoperative positions; bloci the line of wa and means at the block stations rendere o erative by the presence of a predetermined anger condition to control the circuits constraining the safety devices to release the latter to active operation.

. 14. In an electric safety signal system for railways, mechanically operated means for the actuation of cautionary and safety devices; normally closed electric circuits for holding said devices in inoperative positions; block stations along the line of way; means at the block stations rendered o erative by the presence of a predetermined anger con dition to control t e circuits constraining the safety devices to' release the latter to active i railways, normally close 0 operation, and another electric circuit rendered active through a manually operated circuit-closer after a predetermined time 'period, suflicient to permit the full operation of the safety devices, for restoring the ruptured circuits.

15. In an electric safet s nal system for Iiarged electric circuits grouped at ap ropriate stations along the line of way, a c osed circuit extending between each station and the next station and controlled at one station by one of the normally closed circuits at said station, and includin a source of current at said station, and a po arized relay mechanism at the next succeedin' station; means at one station for breaking t e main circuit leading to the next station and thereby rupturing the closed circuits at the second station, means at the third station controlled by the reversed circuit at the second station, for reversing the circuits at said third station, and train carried circuits and signal dev1ces responsive to the reversed and broken circuits to cause the operation of an appropriate signal in accordance with the electric conditions at the particular block station at which the train is located. a

16. In an electric safety signal system-for railwa s, mechanically operated, air-brake contro ling means upon each train; closed electric circuits holding said air-brake means normally inactive; means for opening the electric circuits to cause the application of the brakes; a normally inactive, manually olperative, circuit-closing means for restorin t e continuit of the electric circuits, and other manna ly operated means, operative after a predetermined time limit, to cause the closure of the restoring circuit under the control of the firstnamed manual circuitclosing means.

In testimony that I claim the foregoing as my own, I have hereto affixed my signature in the presence of two witnesses.

GARDNER B. GRAY.

Witnesses:

GEORGE C. BUELL, Manon KERNS. 

